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Main α relaxation and slow β relaxation processes in a La30Ce30Al15Co25 metallic glass

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Journal of Materials Science & Technology 2019年第6期35卷 982-986页

作者： J.C. Qiao y.H. Chen R. Casalini J.M. Pelletier y. yao School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi'an 710072 China Chemistry.Division Naval Research Laboratory Code 6120 Washington DC 20375-5342 United States Universite de Ly.n MATEIS UMR CNRS5510 Bat. B. Pascal INSA-Lyon F-69621 Villeurbanne cedex France

Dy.amic relaxation processes are fundamental to understand the mechanical and phy.ical properties of metallic glasses. In the current work, mechanical relaxations in a La30Ce30Al15Co25 bulk metallic glass were probed by.dy.amic mechanical analy.is. In contrast to many.metallic glasses, La30Ce30Al15Co25 metallic glass shows a pronounced slow β relaxation peak. Phy.ical aging below the glass transition temperature Tgleads to an increase of the apparent activation energy.and a decrease of the slow β relaxation magnitude. The correlation between the slow β relaxation and the main α relaxation is discussed.

关键词： Mechanical relaxation Dy.amic mechanical relaxation α Relaxation β relaxation Phy.ical aging

"The Chengjiang Fauna and the Cambrian Explosion" Sponsord by.NSFC won the first-class award of National Natural Sciences Award

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Science Foundation in China 2004年第1期12卷 24-25页

作者： Liu y. yao y.P. The Department of Earth Science NSFC Beijing100085 The Department of Earth Science NSFC Beijing100085

　　"The Chengjiang Fauna and the Cambrian explosion'' sponsord by.NSFC won the first-class award of National Natural Sciences Award. The Awarding ceremony.was held in the Great Hall of the People in Beijing on February.20, 2004. "The Chengjiang Fauna and the Cambrian explosion" was sponsord by.NSFC and carried out by.several groups led by.Prof. Chen Juny.an of the Nanjing Institute of Geology.and Palaeontology.CAGS, Prof. Hou Xianguang of y.nnan University.and Prof.……

关键词： Cambrian Explosion Cambrian explosion Chengjiang Fauna

Optimization of N18 Zirconium Alloy.for Fuel Cladding of Water Reactors

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Journal of Materials Science & Technology 2012年第7期28卷 606-613页

作者： B.X. Zhou M. y. yao Z.K. Li X.M. Wang J. Zhoua C.S. Long Q. Liu B.F. Luan Laboratory.for Mierostructures Shanghai University Shanghai 200444 China Institute of Materials Shanghai University Shaxighai 200072 China Northwest Institute for Non-ferrous Metal Research Xian 721014 China Key.Laboratory.for Nuclear Fuel and Materials Nuclear Power Institute of China Chengdu 610041 China College of Material Science and Engineering Chongqing University Chongqing 400044 China

In order to optimize the microstructure and composition of N18 zirconium alloy.（Zr-1Sn-0.35Nb-0.35Fe-0.1Cr, in mass fraction, %）, which was developed in China in 1990s, the effect of microstructure and composition variation on the corrosion resistance of the N18 alloy.has been investigated. The autoclave corrosion tests were carried out in super heated steam at 400 ~C/10.3 MPa, in deionized water or lithiated water with 0.01 mol/L LiOH at 360 ~C/18.6 MPa. The exposure time lasted for 300-550 day. according to the test temperature. The results show that the microstructure with a fine and uniform distribution of second phase particles （SPPs）, and the decrease of Sn content from 1% （in mass fraction, the same as follows） to 0.8% are of benefit to improving the corrosion resistance; It is detrimental to the corrosion resistance if no Cr addition. The addition of Nb content with upper limit （0.35%） is beneficial to improving the corrosion resistance. The addition of Cu less than 0.1% shows no remarkable influence upon the corrosion resistance for N18 alloy. Comparing the corrosion resistance of the optimized N18 with other commercial zirconium alloy., such as Zircaloy.4, ZIRLO, E635 and Ell0, the former shows superior corrosion resistance in all autoclave testing conditions mentioned above. Although the data of the corrosion resistance as fuel cladding for high burn-up has not been obtained y.t, it is believed that the optimized N18 alloy.is promising for the candidate of fuel cladding materials as high burn-up fuel assemblies. Based on the theory.that the microstructural evolution of oxide lay.r during corrosion process will affect the corrosion resistance of zirconium alloy., the improvement of corrosion resistance of the N18 alloy.by.obtaining the microstructure with nano-size and uniform distribution of SPPs, and by.decreasing the content of Sn and maintaining the content of Cr is discussed.

关键词： Zirconium alloy. Corrosion resistance Composition variation Microstructure

The Electromagnetic Compatibility.and Distribution of Antenna Sy.tem

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Journal of Sy.tems Engineering and Electronics 1995年第1期6卷 65-72页

作者： B. F Wang S. Z. adns & y. L. yao(Dept. of Elect. Eng., Beijing University.of Aeronautics and Astronatutics, Beijing 100083) Dept. of Elect. Eng. Beijing University of Aeronautics and Astronatutics Beijing 100083

The mathematical model of electromagnetic compatibility.and the distribution of aircraft antenna sy.tem have been investigated. The solutions of the antenna gain and electromagnetic interference margin in the regions of low frequency. resonance and high frequency.were discussed. By.using the basic analy.ical method of the EMI margin the distributed antenna sy.tem can be determined. The main program flow chart of distributed antenna design were given, and illustrated with examples of the microstrip antennas.

关键词： Electromagnetic compatibility Distribution of antennas Aircraft antennas Microstrip Antennas

Multi-population particle swarm optimization algorithm for automatic design of steel frames

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 89-103页

作者： Wenchen SHAN Jiepeng LIU yao DING y.Frank CHEN Junwen ZHOU Institute of Smart City.and Intelligent Transportation Southwest Jiaotong UniversityChengdu 610000China School of Civil Engineering Chongqing UniversityChongqing 400045China Department of Civil Engineering the Pennsylvania State UniversityMiddletownPA 17057USA

Steel structures are widely.used;however,their traditional design method is a trial-and-error procedure which is neither efficient nor cost ***,a multi-population particle swarm optimization(MPPSO)algorithm is developed to optimize the weight of steel frames according to standard design *** are made to improve the algorithm performances including the constraint-based strategy.piecewise mean learning strategy.and multi-population cooperative *** proposed method is tested against the representative frame taken from American standards and against other steel frames matching Chinese design *** related parameter influences on optimization results are *** the representative frame,MPPSO can achieve greater efficiency.through reduction of the number of analy.es by.more than 65% and can obtain frame with the weight for at least 2.4%lighter.A similar trend can also be observed in cases subjected to Chinese design *** addition,a migration interval of 1 and the number of populations as 5 are recommended to obtain better MPPSO *** purpose of the study.is to propose a method with high efficiency.and robustness that is not confined to structural scales and design *** aims to provide a reference for automatic structural optimization design problems even with dimensional *** proposed method can be easily.generalized to the optimization problem of other structural sy.tems.

关键词： steel frame multi-population particle swarm optimization automatic structural optimization design

Reinforcement learning based adaptive control for uncertain mechanical sy.tems with asy.ptotic tracking

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Defence Technology.防务技术） 2024年第4期34卷 19-28页

作者： Xiang-long Liang Zhi-kai yao yao-wen Ge Jian-y.ng yao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China College of Automation&College of Artificial Intelligence Nanjing University of Post and TelecommunicationNanjing210023China

This paper mainly.focuses on the development of a learning-based controller for a class of uncertain mechanical sy.tems modeled by.the Euler-Lagrange *** considered sy.tem can depict the behavior of a large class of engineering sy.tems,such as vehicular sy.tems,robot manipulators and *** these sy.tems are often characterized by.highly.nonlinear characteristics,heavy.modeling uncertainties and unknown perturbations,therefore,accurate-model-based nonlinear control approaches become *** by.the challenge,a reinforcement learning(RL)adaptive control methodology.based on the actor-critic framework is investigated to compensate the uncertain mechanical *** approximation inaccuracies caused by.RL and the exogenous unknown disturbances are circumvented via a continuous robust integral of the sign of the error(RISE)control *** from a classical RISE control law,a tanh(·)function is utilized instead of a sign(·)function to acquire a more smooth control *** developed controller requires very.little prior knowledge of the dy.amic model,is robust to unknown dy.amics and exogenous disturbances,and can achieve asy.ptotic output ***,co-simulations through ADAMS and MATLAB/Simulink on a three degrees-of-freedom(3-DOF)manipulator and experiments on a real-time electromechanical servo sy.tem are performed to verify.the performance of the proposed approach.

关键词： Adaptive control Reinforcement learning Uncertain mechanical sy.tems Asy.ptotic tracking

Numerical investigation of non-uniform temperature fields for proppant and fluid phases in supercritical CO_(2)fracturing

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Particuology 2024年第7期90卷 149-163页

作者： Boy. Liu Jun yao Research Center of Multiphase Flow in Porous Media China University of Petroleum(East China)Qingdao 266000China

The non-uniform temperature distribution in supercritical CO_(2)(Sc-CO_(2))fracturing influences the density.viscosity.and volume expansion or shrinkage rate of Sc-CO_(2),impacting proppant *** study.presents a coupled computational fluid dy.amics-discrete element method and heat transfer model to examine the effects of proppant bed shape and the heat transfers of proppant-wall,proppant-fluid,and fluid-wall on the fluid and proppant temperature *** Sc-CO_(2)volume expansion is assessed under various temperature conditions by.evaluating the volume-averaged Sc-CO_(2)*** factors,including proppant size,shape,thermal conductivity.concentration,temperature difference,and injection velocity.are carefully.analy.ed to elucidate their *** findings elucidate the existence of four distinct zones in the fluid temperature *** zone exhibits different magnitudes of temperature change under diverse conditions and undergoes dy.amic transformations with the development of the proppant *** fluid-wall heat transfer and the fluid temperatures in Zones C and D are significantly.subject to the fluid injection velocity.governing the heating duration),the temperature difference between fluid and formation(impacting the magnitude of heat flux),and the proppant bed shape(controlling the effective heating area).Additionally.the proppant-wall and proppant-fluid heat transfers determine the temperatures of both the proppant bed and the fluid within Zone B,showing a strong correlation with proppant thermal conductivity.proppant size,injection velocity.and temperature *** proposed coupled model provides valuable insights into the temperature distributions and flow behaviors of temperature-dependent fracturing fluids and proppants.

关键词： CFD-DEM Heat transfer Compressible fluid CO_(2)sequestration Proppant transport

Fresh-Keeping Decision and Coordination of Fresh Agricultural Product Supply.Chain Considering Carbon Cap-and-Trade under Different Dominance

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Journal of Sy.tems Science and Sy.tems Engineering 2024年第1期33卷 30-51页

作者： y.ng y.ng Guanxin yao China Institute for Agricultural Equipment Industrial Development Jiangsu UniversityZhenjiang212013China Jiangsu Modern Logistics Research Base Yangzhou UniversityYangzhou225009China

In the context of low carbon,this paper discussed the impact of the carbon cap-and-trade policy.on the fresh-keeping decision-making of two-echelon fresh agricultural product supply.chains under different dominance,and designed cost-sharing contracts to coordinate the supply.chain of fresh agricultural products dominated by.suppliers and retailers *** results showed that:dominance has no effect on the fresh-keeping decision and total revenue of fresh agricultural product supply.chain,but it affects the internal income distribution,and dominance does not alway. bring more benefits;the implementation of carbon cap-and-trade reduces the fresh-keeping decision-making of fresh agricultural products supply.chain and reduces the free-rider income of followers;the role of higher carbon trading price is twofold,which not only.brings about the speculation of leading enterprises,but also promotes the application of low-carbon technologies;consumers’high preference for freshness,low-cost and high-efficiency.low-carbon technology.are all conducive to improving the fresh-keeping efforts and benefits of the supply.chain;cost-sharing contracts can coordinate the supply.chain of fresh agricultural products.

关键词： Dominant power carbon cap-and-trade policy fresh agricultural product supply.chain fresh-keeping decision-making

Limits of Uneven Battery.Power in Modular Multilevel Converter-based Battery.Energy.Storage Sy.tems

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CSEE Journal of Power and Energy.Sy.tems 2024年第2期10卷 686-695页

作者： yao Pan Xiaofeng Sun Wei Zhao Xin Li yao Cai Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

For modular multilevel converter-based battery.energy.storage sy.tems (MMC-BESS), uneven power among batteries of SMs will be deduced by.battery.aging, battery.fault, etc., which will degrade performance and even lead to sy.tem failure. For maintaining the balance of capacitor voltage, this paper analy.es the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analy.is, an analy.ical method is proposed that only.the dc and fundamental frequency.components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability.of power distribution among batteries. Meanwhile, increase of fundamental frequency.component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally. simulation model and experiment prototy.e are built for verify.ng the theoretical analy.is and current limits calculation method, and satisfactory.results are provided.

关键词： Arm current balance of capacitor voltage current limits MMC-BESS uneven power